391965 has 16 divisors (see below), whose sum is σ = 716928. Its totient is φ = 179136.

The previous prime is 391961. The next prime is 391967. The reversal of 391965 is 569193.

It is not a de Polignac number, because 391965 - 2² = 391961 is a prime.

It is a super-2 number, since 2×391965² = 307273122450, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1762 + ... + 1971.

It is an arithmetic number, because the mean of its divisors is an integer number (44808).

2³⁹¹⁹⁶⁵ is an apocalyptic number.

391965 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

391965 is a deficient number, since it is larger than the sum of its proper divisors (324963).

391965 is a wasteful number, since it uses less digits than its factorization.

391965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3748.

The product of its digits is 7290, while the sum is 33.

The square root of 391965 is about 626.0710822263. The cubic root of 391965 is about 73.1839359775.

The spelling of 391965 in words is "three hundred ninety-one thousand, nine hundred sixty-five".